Art and apparatus for making printing-surfaces



S. H. HORGAN.

ART AND APPARATUS FOR MAKING PRINTING SURFACES.

Mmc/1110:: man sEPT.13, 1919.

1,340,342. Patented `May 18, 1920.

A TTORNEY STEPHEN H. HORGAN, OF ORANGE, NEW JERSEY.

ART AND APPARATUS FOR MAKING PRINTING-SURFACES.

Specification of Letters Patent.

' Patented May 18, 1920.

Application filed September 13, 1919. Serial No. 323,509.

To all whom lt may concern.'

Be it known that I, STEPHEN H. HORGAN,

carbon tissue or gelatin film carrying a design to the surface of the copper roller used in rotogravure without stretching or distorting the film, thus enabling exact register between separate transfers to be realized. The copper cylinders after etching may be used to print in colors either on paper for illustrative or decorative purposes or for -the printing on fabrics of cotton, silk or other material as in textile printing. The cylinders, although usually carrying their design in intaglio may also carry them in relief. One of the objects of my invention is to prevent the distortion, stretching and shrinkage that takes place when carbon tissue is used in the production of printing cylinders in the process of rotary photogravure.

Another object ofmy invention is tc prevent the distortion, stretching and shrinkage that takes place when several carbon tissues are used in the production of multicolor printing in the process of rotary photogravure when photography and color filters are used to separate the colorsas in threecolor and four-color relief engraving.

Anofther object of my invention is to facilitate the production fromv a colored design .of color 'separations in a rapid and artistic manner. These color separations are, by the Ben Day method of makingcolor plates, turned into positives for printing photographically on several sheets of carbon tissue as used in the process of rotary photogravure. I utilize the Ben Day or shading film method of making color printing plates in one step in the-making of the separation gelatin prints, thus forming special design surfaces suitable for printing in rotogravure.

Still another object of my invention is to enable the transferring of several sheets of carbon tissue to printing cylinders, each of such sheets of carbon tissue carrying partial designs representing different colors, these different sheets of carbon tissue being prevented, by my invention from distortion, stretching and shrinkage, so that when these different partial designs are etched and printed from in their different colors, superimposed upon each other, it Will be found that the resulting colored impressions will be in exact register and produce an artistic multicolor picture or print.

In the present method of etching copper rolls for printing in one color in rotary photogravure, a photographic print is made on carbon tissue which, after being moistened is pressed against the surface of the copper roll and dried there. The necessary moistening of the carbon tissue stretches and distorts it, so greatlyV that it is found impractical to use this method in multicolor printing Where several carbon tissues, each one representing a color, are moistened and attached to separate copper rolls, as the unequal stretching and distortion of the different sheets of carbon tissue Would prevent the perfect register of the colors when printing.

The carbon tissue used in this process is of an exceeding hygroscopic nature, absorbing moisture from the air and giving off its moisture at every change in the humidity of the room in which it is. As the gelatin in this 'carbon tissue absorbs moisture it expands and on giving off moisture it shrinks, or contracts, so that it is impossible at present to keep carbon tissue at precisely the same dimensions during the operations of wetting and drying through Which it has to pass during the process of rotary photogravure. A further obstacle to maintaining precise dimensions of the carbon tissue is due to the paper backing' or support for the gelatin film or carbon tissue. This paper is also hygroscopic but When absorbing moisture it stretches most across the fibers in the paper and least in the direction in which the ibers point as the paper comes from the machine on which it is made. Consequently the paper stretches unequally in the two directions, which might be termed its length and breadth.

My invention provides a non-hygroscopic perforated metal backing for the gelatin tissue which prevents stretching or shrinking of either the gelatin of which the tissue is composed or the paper on which it is supported so that hygroscopic changes or Wetting and drying have no effect upon the gelatin tissue during the operations of rotary photogravure.

The carbon tissue consists of a gelatin coated sheet or strip of paper mixed with carbon or other coloring matter upon which a print has been made by photography. rThe gelatin side of the carbon tissue containing the photographic print must now be secured in intimate contact with a copper roller in order that the etching of the roller, which etching takes place through the gelatin, may be properly carried out. T o secure this intimate contact the carbon tissue is either soaked in water, or in a mixture of water and alcohol or one edge of the carbon tissue is secured to a line on the top of the copper roller parallel with the axis of the roller. Then a spray of water is projected between the surface of the carbon tissue and the copper roller, the object of each one of these different methods being to render the surface of the carbon tissue so adhesive that when pressed around the copper' roller every partof its surface will be in intimate contact with the copper roller. The next step is to remove the paper support from the carbon tissue. Thisis done by pouring hot water over the paper support until some of the carbon or other pigment in the tissue begins to ooze out at the edges of the paper when the paper can be peeled from the carbon tissue. Development of the carbon tissue is now done with warm water until only the portions of the carbon tissue hardened by the action of light during the previousl operation of photographic printing remains in intimate contact with the copper roller. The next step is the etching step. Chlorid of iron is applied to the gelatin film and penetrates first where the film is thin and last where the film is thickest. This etches the copper to different depths and subsequently when the copper cylinder is inked, gives gradations of shade in rotogravure. The design on the copper roller is broken up into ink-containing cells or lines by the interposition of a half-tone screen which has been utilized when producing the print or image upon the gelatin film. Owing to the wetting, developing and transferring of the carbon tissue sheet it is unequally stretched and distorted, which would prevent perfect register if an attempt were made to use it in color printing.

In accordance with an embodiment of my invention I first make a key plate of the picture to be printed in colors. This key plate is made preferably by the rotary photogravure method.

As many proofs of this key plate are then printed in ink upon sheets of bristolboard as there are to be colors printed later.

A color artist or lithographie artist thereupon with the original colored picture before him paints-upon each of the proof designs carried by thev bristolboard, a portion of the picture in its proper color. In this way one obtains a black key plate impression upon bristolboard and the several color separations into which the original picture is divided.

In accordance with my invention I transform the color separations into surfaces which can be readily Vprinted in the rotogravure manner and which can be quickly and artistically produced. Accordingly I superimpose upon the bristolboard sheets carrying the color separations in colors, transparent films which may be Celluloid, one over each separate picture. The colors show through the transparent films. A Ben Day artist now transfers upon the celluloid by means of a shading film suitably inked 011 -one side, the dots or lines carried by the film. He places the dots where he finds the color on the bristolboard beneath. In this way the celluloid sheets have transferred to them in black ink the Ben Day or shading medium color values or shades corresponding to the color separations on the bristolboard beneath. These Celluloid sheets are then used as positives to print on the gelatin face of the carbon tissue. Contact prints are made, the Celluloid sheets being put into a printing frame, with the gelatin films next to them.

In order to prevent distortion of the gelatin film, its expansion or acontraction, I provide, in accordance with my invention, a perforated backing for the carbon tissue sheet. This backing Will prevent the distortion of the hygroscopic gelatin both while the gelatin is being subjected to the heat during the operation of photographic printing close to powerful electric arc lamps or later during the wetting of the surface of the carbon tissue to render its surface adhesive while it is being brought into intimate contact with the copper roller.

In the best embodiment of my invention I cement the paperback of the carbon tissue strip to sheets of perforated, flexible metal such as zinc by means of shellac or similar cement not soluble in' water.

In carrying out my invention the gelatin l coated paper known as carbon tissue is made sensitive to the action of light by imm'ersing in a solution of potassium bichromate in water for two or three minutes after which it is pressed with the gelatin side, in contact with a plate glass or enameled ferrotype plate and left to dry, or it is dried ina current of air developed by an electric fan. This drying is done in a dark room as the carbon tissue when dry is sensitive to light action.

lVhen the carbon tissue is thoroughly dry, in contact with the plate glass or ferrotype plate, the back of the paper support, covering the sensitized carbon tissue is brushed over withl a coating of shellac in alcohol and a piece of thin perforated sheet metal preferably zinc vis pressed in contact with the shellac-coated paper support of the carbon tissue. This pressure on the perforated metal backing is maintained in a press or by laying flat weights on it until the alcohol in the shellac evaporatesthrough the perforations in the metal backing and this backing is cemented securely to the paper support of the carbon tissue.

The pressure being removed it will be found that the carbon tissue can be detached from the plate glass or ferrotype plate to which it was secured during the operation of drying, and that itadheres rigidly to the perforated metal backing.

The carbon tissue is now placed in the photographic printing frame in contact with the positive from which it is to take an image by the action of light through the positive. The light used is a powerful electric one from which much heat radiates and which would have a tendency to contract the carbon tissue were it not held securely from contraction by the metal backing.

The next step in the operation, after getting the image on the carbon tissuel by the action of light, just described, is to wet the surface of the carbon tissue, either with water or, a mixture of water and alcohol to render the surface of the carbon tissue tacky so that it will stick to the copper cylinder. Here the carbon tissue would stretch were it not for the perforated, fiexible metal backing. So the carbon tissue is wet, and with its perforated, fiexible metal backing is pressed around the copper cylinder and held there for a few minutes until the carbon tissue has attached itself firmly to the copper cylinder. It dries there in a few minutes owing to the rapid evaporation of the. water throu h the perforationsvin the metal backing. hen dry, alcohol is poured over the perforations in the metal backing. This alcohol quickly dissolves the shellac which held the metal backing to the paper support of the carbon tissue. The backing releases itself and the carbon tissue is left secured to the copper cylinder without distortion, stretching or shrinkage.

The next step is to remove the paper support of the carbon tissue and this is done by revolving the cylinder in a trough of water heated to a temperature sufiicient to soften the gelatin of the tissue unhardened by the action of light. This is determined by lthe carbon color in the tissue oozing out at the edges of the paper support. The paper support can now be taken at a corner and gently stripped away from the carbon tissue leaving the film of carbon tissue, which has been acted upon by light, firmly attached lto the copper cylinder. This carbon image on the copper cylinder can be further developed carbon tissue resist.

with warm Water after which it is set with cold water and dried when it is-ready for etching the copper c linder through this he wetting of the paper support during the above operation cannot change the dimensions of the carbon tissue because that became fixed immovably' to the copper cylinder when it was pressed in contact with the copper cylinder with the perforated metal backing, thus securing the carbon tissue from expansion or contraction. The metal backing of the carbon tissue keeps the latter rigid and prevents distortion while the image on the carbon tissue is being printed (when it is subjected to a high temperature) as well as when the gelatin face of the carbon tissue is moistened with alcohol and Water and pressed around the copper roll in transferring the design to the latter. The metal backing, moreover, being fiexible, bends easily around the surface of the copper roll and is held there until the moisture in the carbon tissue evaporates through the perforations in the metal. The warm water which has been poured over the paper backing softens the gelatin immediately under it which has been unacted upon by light and the paper comes away leaving the gelatin 'Whiclr has been acted upon by light to unequal depths firmly attached to the surface of the copper roll. The etching of the design by subjecting the gelatin film to an etching bath while on the roll can then be proceeded with. I make use of zinc for the metal backing but other vmetals may be used. The perforations in the zinc are preferably round but may have any desired shape or distribution. The perforations permit the evaporation of the alcohol from the cement used in attaching the carbon tissue to the metal backing and also permit the alcohol to react and dissolve the cement when detaching the metal backing from the carbon tissue after transferring the tissue to the cylinder.y

I have illustrated in the accompanying drawings one embodimentof my invention and one way `of carrying my process into effect.

Figure 1 illustrates the five impressions from a key plate upon bristolboard as would be used in making printing surfaces to print in black and four colors.

F ig. 2 illustrates the second step in the process in which each color separation has been placed upon the bristolboard.

Fig. 3 illustrates the next step in which after placing celluloid or transparent sheets over the partial pictures, a Ben Day artist has transformed the color values of the separation colors of Fig. 2 into dots by the use of the Ben Day film. The Celluloid sheet is shown broken away in one view.

Fig. 4 is a multicolor original picture in five colors which it is intended to reproduce.

Figs. 5 and 6 indicate a plan and a section of a metal backing sheet.

Fig. 7 illustrates the metal backing sheet carrying, the carbon tissue, z'. e. the gelatinv coated paper. n Fig. 8 shows the operation of transferring the design from the carbon tissue to a metal roller. '1.

Fig. 9 shows the step of removing the metal backing sheet.

. Fig. 10 shows the step of removing the paper support from the. gelatin film.

Referring to the drawings, the photoengraver first makes the key plate a print from which is illustrated at a in Fig. l. The key plate carries the outline of the complete design and any additional shades or shadows that may be desired. This keyplate is made by the rotary photogravure process as is customary in making key plates or printing plates for printing rotary photogravure in monotone. It carries a sunken or intaglio design made up of ink retaining cells or lines. From this key plate a print is taken for each separation plate that is to be made. The prints b, c, d, e of Fig. 1 are taken from the key .plate on bristolboard, so

as to make separation plates to print in yellow, red, blue, and brown, for example.

A color artist or lithographer now takes the original colored subject illustrated in Fig. 4 and with it as a'guide for his eye, he dissects the color values of the picture, as

customary in lithography, and paints upon thevprints b, c, d, e the colors of which the picture is composed. At B of Fig. 2 the artist'places the yellow component of the p)icture, at C of Fig. 2 he paints the red, at

the blue and at E the brown. The colors are indicated on the drawing by conventional shade lines. He is guided and aided in so placing the colors by the outline key print on the bristol board which has been printed thereon from the key plate.

In accordance with my invention these separate prints' are now to be rapidly and artistically transformed into printing surfaces. In the best embodiment of my invens tion I utilize the Ben Day method of manipulatin shading mediums. A Celluloid sheet K is rst placed over each of the designs shown in Fig. 2 at B, C, D, and E. The Ben Day artist then places his shading machine carrying a Ben Day or similar film over the celluloid sheet and having inked the face of the film in the customary manner he by means of the tool or stylus rubs the back of the film in the usual way and transfers to the celluloid yat the portions where the partial designs show throughv in their colors, the dots on the face of the Ben Day films. fers. Thisv step of the process is illustrated in Fig. 3 at B', C', D, E. The Celluloid sheet K is shown broken away at B. The

' atives.

He chooses the film that he pre` artist may use any film which is suitable for getting the particular effect desired. In Fig. 3 for instance he may use for the partial design B, Ben Day film Number 310. For partial design C he may use Number v426 and Vfordesign D Number 306 and for with Ben Day dots or lines., these Celluloid sheets are used as transparencies or positives to print by the action' of light passing through the sheets onto thegelatin face of the carbon tissue. The carbontissue has been previously sensitized and backed by my perforated zinc or metal backing sheets. The image is then wet to render its surface adhesive and transferred face down to the copper roller as shown in Fig. 8. Alcohol is then poured over the perforated backing sheet and the backing sheet stripped from the carbon tissue as shown in Fig. 9. The alcohol dissolves the shellac cement between the backing sheet and the carbon tissue paper. The paper of the carbon tissue is then soaked from the gelatin face which it carries by means of warm water and stripped off as shown in Fig. 10. This leaves the gelatin side carr ing the image upon the carbon roller. hlorid of iron or other etching solution is then poured on the gelatin and etches the copper roller to different depths according 4to the way the gelatin has been acted upon by light, the latter being thicker and thinner in accordance with `the light action. The several partial plates may thus be transferred in exact register to the different copper rollers. Each of them is broken up into Ipnt or line designs as carried by the Ben ay films.

The backing sheet number l is provided with the perforations 2 and has cemented to it the carbon tissue consisting of 'a paper sheet 3 faced with a gelatin sheet 4. The copper roller is designated 5.

Instead of using the Ben Day method of separating the colors for multicolor printing bv the rotary photogravure method, I may utilize the three or four color photographic process for makingthe color separation neg- From these negatives positive transparencies are made to be printed from photographically on sensitized carbon tissue backed up with my perforated metal backing. In this way distortion, expansion or contraction of the colored images is pre- `departing from the principle of the invention.

What I claimas new and desire to secure by Letters Patent is:

1. The process of making color separa- 'tion cylindrical printingsurfaces which conslsts in-making a key printing surface,

printing a plurality of impressions from said key surface, painting upon the several impressions the component colors of `the multicolor print to be reproduced, covering said paintings with transparent sheets,

transferring marks from a shading film to said transparent sheets at the places where the color shows through, backing a carbon tissue with a metallic backing, photo-printing through -said marked transparencies upon the gelatin surface of the sensitized carbon tissue, transferring said gelatin surfaces while so backed to the surfaces of metal rollers, removing said metallic backing and transforming said rollers into rotogravure printing surfaces.

2. The process of making color separation cylindrical printing surfaces which consists in mounting carbon tissue upon a metal backing, preparing a series of color separation transparencies, photo-printing through each of said transparencies upon the gelatin surface of the carbon tissue, wetting said surfaces, transferring said wetted gelatin surfaces while backed to the surfaces of a series of copper cylinders, removing said metal backing, removing the paper from the carbon tissue leaving the gelatin surfaces upon the copper cylinders and transforming the surface of the copper cylinders into printing surfaces whereby they are adapted to print a multi-color picture in register.

3. The process of making color separation cylindrical printing surfaces which consists in making a key plate, printing a plurality of impressions from said plate, painting upon the several impressions the component colors of the multicolor print to be reproduced, covering said paintings with transparent sheets, transferring marks Yfrom a shading film to said transparent sheets at the places where the color shows through, cementing a -metallic perforated backing to the paper side of the carbon tissue, photo-printing through said marked transparencies upon .the gelatin surface of the sensitized carbon tissue, transferring said gelatin prints while so backed to the surfaces of metal rollers, dissolving the cement so as to remove the metallic perforated backing and thereupon transforming said rollers into printing surfaces adapted to print colors in register.

4. The process of making colorl separation cylindrical printing surfaces which consists in painting the component colors of the multicolor print to be reproduced, covering said paintings with transparent sheets, transferring marks from a shading film to said transparent sheets at the places Where the color shows through, shellacking a metallic perforated backingto 1the paper side of the carbon tissue, photo-printing through said marked transparencies upon the gelatin surface of the sensitized carbon tissue, transferring said gelatin prints while so backed to the surfaces of metal rollers, applying alcohol through the perforations of the backing so as to dissolve the shellac and thus remove the metallic perforated backing and thereupon transforming said rollers into printing surfaces adapted to print colors in register.

5,. The process of making color separation cylindrical printing44 surfaces which consists in cementing carbon tissue upon a perforated metal backing plate, preparing al series of color separation transparencies, photo-printng through each of said transparencies upon the gelatin surface of the carbon tissue, wetting said surfaces, transferring said wetted vgelatin surfaces while backed to the surfaces of copper cylinders, dissolving the cement by pouring alcohol through the perforations of the metal backing, removin the backing, removing the paper from t e carbon tissue so as to leave the gelatin upon the cylinders and transforming thel surface of the cylinders into printing surfaces so as to print in register.

6. A backed carbon tissue for use in transferring designs lupon metal cylinders to be thereafter developed into printing surfaces consisting of a perforated metal backing sheet and a carbon tissue sheet formed of a gelatin coated paper, the paper side of which has been cemented to the backing.

7. A backed carbon tissue for use in transferring designs uponmetal cylinders to be thereafter developed intoprinting surfaces consisting of a perforated metal backing sheet and a carbon tissue formed of a gelatin coated paper and a shellac cement for cementing the paper side of the carbon sheet to the `backing.

In testimony whereof I have signed my name to this specification.

' STEPHEN H. HORGAN. 

